ORLANDO, Fla. — Authorities investigating the apparent suicide of a college student discovered weapons and explosive devices in a dorm on the University of Central Florida campus in Orlando early Monday, and hundreds of students were evacuated, though the school said there was no immediate threat.

University police were called to the dorm around 12:20 a.m. after a fire alarm went off, UCF spokesman Grant Heston said. While they were on their way to the scene, a 911 call came in about a man with a gun.

Arriving officers found a man dead from what appeared to be a self-inflicted gunshot wound inside a residence at the Tower 1 dorm. Heston said the man was a student at the university.

Heston said the dorm has suites, with a main kitchen and living area, along with four bedrooms. The dead man was inside one of the rooms. Inside the room, police also found what they described as an assault weapon, a handgun and improvised explosive devices.

Heston said the Orange County Sheriff's Office and the FBI are helping with the investigation. The sheriff's bomb squad was examining the explosive devices Monday morning.

About 500 students were evacuated from the dorm and an adjacent parking garage was closed initially.

"We don't believe there is any imminent threat to the campus," Heston said.

The university canceled classes through noon Monday as a precaution. Flashing signs around the campus alerted students and staff about the cancelled classes. Campus shuttle buses were lined up about a half-mile from campus, with drivers standing by once the campus opens.

Antonio Whitehead, 21, a junior from Hollywood, Fla., said he heard the fire alarm go off after midnight and thought it was a routine alarm. He headed outside where he saw a crowd already heading across the street from the dorm.

"All of a sudden, I felt the crowd move a little faster. And a police officer with a machine gun or something told everyone to start moving a lot faster," he said.

Whitehead, who has lived in the dorm for two years, said the students were moved to an open area about 1,000 feet from UCF Arena. The area is a busy section of the campus, with restaurants and shops nearby.

Grant Hernandez, 20, a sophomore from Orlando who also is a resident at the dorm, said he woke up sometime after midnight when police were evacuating the building.

"All we saw were people running, and they were not telling us what was going on," he added. "We were left unsure of things. It wasn't till about 6 o'clock that we got more information and a clearer picture of what was going on." He said officers on the scene began providing more information, and students checked updates on the university's website.

A statement there said the UCF Arena would open to accommodate displaced students. Counselors would be available to talk to students who need assistance.

A spokeswoman for State University System Chancellor Frank Brogan said he was called this morning by UCF President John Hitt and told about the situation unfolding on campus.

"As far as we know no other students are in danger," Kim Wilmath said.